/*
 * Copyright (C) 2011 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.common.math;

import static com.google.common.math.MathBenchmarking.ARRAY_MASK;
import static com.google.common.math.MathBenchmarking.ARRAY_SIZE;
import static com.google.common.math.MathBenchmarking.randomDouble;
import static com.google.common.math.MathBenchmarking.randomPositiveDouble;

import com.google.caliper.BeforeExperiment;
import com.google.caliper.Benchmark;
import com.google.caliper.Param;
import java.math.RoundingMode;

/**
 * Benchmarks for the rounding methods of {@code DoubleMath}.
 *
 * @author Louis Wasserman
 */
public class DoubleMathRoundingBenchmark {
    private static final double[] doubleInIntRange = new double[ARRAY_SIZE];
    private static final double[] doubleInLongRange = new double[ARRAY_SIZE];
    private static final double[] positiveDoubles = new double[ARRAY_SIZE];

    @Param({"DOWN", "UP", "FLOOR", "CEILING", "HALF_EVEN", "HALF_UP", "HALF_DOWN"})
    RoundingMode mode;

    @BeforeExperiment
    void setUp() {
        for (int i = 0; i < ARRAY_SIZE; i++) {
            doubleInIntRange[i] = randomDouble(Integer.SIZE - 2);
            doubleInLongRange[i] = randomDouble(Long.SIZE - 2);
            positiveDoubles[i] = randomPositiveDouble();
        }
    }

    @Benchmark
    int roundToInt(int reps) {
        int tmp = 0;
        for (int i = 0; i < reps; i++) {
            int j = i & ARRAY_MASK;
            tmp += DoubleMath.roundToInt(doubleInIntRange[j], mode);
        }
        return tmp;
    }

    @Benchmark
    long roundToLong(int reps) {
        long tmp = 0;
        for (int i = 0; i < reps; i++) {
            int j = i & ARRAY_MASK;
            tmp += DoubleMath.roundToLong(doubleInLongRange[j], mode);
        }
        return tmp;
    }

    @Benchmark
    int roundToBigInteger(int reps) {
        int tmp = 0;
        for (int i = 0; i < reps; i++) {
            int j = i & ARRAY_MASK;
            tmp += DoubleMath.roundToBigInteger(positiveDoubles[j], mode).intValue();
        }
        return tmp;
    }

    @Benchmark
    int log2Round(int reps) {
        int tmp = 0;
        for (int i = 0; i < reps; i++) {
            int j = i & ARRAY_MASK;
            tmp += DoubleMath.log2(positiveDoubles[j], mode);
        }
        return tmp;
    }
}
